Generally, the applications of high-speed latches and flip-flops are widespread. In designing digital circuits, high-speed latches and flip-flops are widely used for sampling and storing/holding data. For example, a current-mode logic latch circuit (also referred hereinafter as a latch circuit) is widely-used because the differential architecture of the latch circuit can increase the operating speed and reject the common mode noise. Since the trends of designing circuits are toward miniaturization and high frequency application, it is important for the latch circuit to accurately sample and latch input signals.